Description
In the Linux kernel, the following vulnerability has been resolved:

forcedeth: fix off-by-one when saving/restoring non-PCI config space

nv_suspend() and nv_resume() walk the non-PCI configuration space with

for (i = 0; i <= np->register_size/sizeof(u32); i++)

which runs one iteration too many. saved_config_space is declared as

u32 saved_config_space[NV_PCI_REGSZ_MAX/4];

and NV_PCI_REGSZ_VER3 is equal to NV_PCI_REGSZ_MAX (0x604), so on a VER3
device register_size/sizeof(u32) is exactly the array length and the last
iteration addresses one element past the end.

The element it lands on is np->name_rx[0..3]: saved_config_space[] is
followed immediately by char name_rx[IFNAMSIZ + 3], and char needs no
padding. Nothing observable is corrupted by that, because nv_request_irq()
rewrites name_rx with sprintf() before it is ever passed to request_irq().
The bug is the out-of-bounds access itself, which UBSAN reports and which
CONFIG_UBSAN_TRAP=y turns into a trap that aborts the running kernel code,
plus an MMIO read and, on resume, an MMIO writel() to base + 0x604, one
dword past the range the driver mapped:

np->base = ioremap(addr, np->register_size);

VER1 and VER2 devices stay inside the array, but they too get the stray
read and the stray write one dword past their own window.

Caught by UBSAN on an Apple Macmini3,1 (MCP79) during a deep S3 cycle.
The splat below is trimmed: the build path in the file name, the CPU
and taint lines, the Workqueue line, the "?" hint frames, and the
frames below device_suspend are all cut. The kernel was tainted, with
an out-of-tree nouveau and CPU_OUT_OF_SPEC; forcedeth itself was the
stock module.

UBSAN: array-index-out-of-bounds in drivers/net/ethernet/nvidia/forcedeth.c:6225:25
index 385 is out of range for type 'u32 [385]'
Call Trace:
dump_stack_lvl+0x5d/0x80
ubsan_epilogue+0x5/0x2b
__ubsan_handle_out_of_bounds.cold+0x54/0x59
__this_module+0xe398c/0xe9010 [forcedeth]
pci_pm_suspend+0x80/0x170
dpm_run_callback+0x51/0x160
device_suspend+0x1a2/0x4a0
...

Both loops are hit. UBSAN reports each source location only once per module
load (__ubsan_handle_out_of_bounds() calls suppress_report(), which does
test_and_set_bit(REPORTED_BIT, ...) on the struct source_location), so the
two splats land in the first S3 cycle after the module is loaded and later
cycles are silent even though the access still runs off the end every time.
In that first cycle line 6225 is reported from pci_pm_suspend and line 6240
from pci_pm_resume.

The same off-by-one was fixed in nv_get_regs() by commit ba9aa134287f
("forcedeth: fix buffer overflow") in 2012; these two loops were missed.
The suspend and resume side was reported on LKML in September 2013 by Marc
Weber, with the same analysis and the same one-character fix, but the patch
was attached rather than sent inline and the thread ended there.

Use < instead of <=, which saves and restores exactly register_size bytes.
Published: 2026-09-11
Score: 7.1 High
EPSS: < 1% Very Low
KEV: No
Impact: Kernel Crash / Denial of Service
Action: Patch
AI Analysis

Impact

An off‑by‑one error in the forcedeth driver causes the nv_suspend() and nv_resume() routines to read and write one element past the end of a statically allocated array while copying non‑PCI configuration space. The out‑of‑bounds access can trigger a UBSAN trap that aborts the kernel, or silently perform an invalid device registers. The outcome is a kernel crash that brings the affected system down, representing a denial‑of‑service condition rather than a direct privilege escalation or data exposure.

Affected Systems

All Linux kernels that include the forcedeth driver without the loop‑bound fix commit (changing '<=' to '<') and that support suspend/resume of devices using this driver are impacted. Any distribution or custom kernel carrying the unpatched forcedeth module is vulnerable.

Risk and Exploitability

The CVSS score of 4.7 indicates medium severity, and the EPSS score is below 1%, indicating a very low probability of exploitation. The vulnerability is not listed in CISA KEV. Based on the description, it is inferred that an attacker would need local system access or the ability to trigger suspend/resume cycles for a device managed by forcedeth to exploit the flaw—e.g., by sending a power‑management event or manipulating the power state. Because the fault leads to a kernel abort when UBSAN is enabled, the impact is largely confined to system availability rather than confidentiality or integrity. The overall risk is moderate and most relevant in environments using legacy Linux kernels with the forcedeth driver and enabled suspend/resume.

Generated by OpenCVE AI on September 13, 2026 at 04:38 UTC.

Remediation

No vendor fix or workaround currently provided.

OpenCVE Recommended Actions

  • Update the Linux kernel or driver package to a version that incorporates the forcedeth off‑by‑one fix (commit that changes the loop to use ‘<’ instead of ‘<=’)
  • If an immediate kernel update is not feasible, disable or blacklist the forcedeth kernel module until a patch can be applied
  • Configure the kernel with UBSAN enabled and trap mode to break early on array‑index violations, thereby preventing silent corruption though it may result in a kernel panic

Generated by OpenCVE AI on September 13, 2026 at 04:38 UTC.

Tracking

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Advisories

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History

Sun, 13 Sep 2026 06:45:00 +0000

Type Values Removed Values Added
Metrics cvssV3_1

{'score': 4.7, 'vector': 'CVSS:3.1/AV:L/AC:H/PR:L/UI:N/S:U/C:N/I:N/A:H'}

 cvssV3_1

{'score': 7.1, 'vector': 'CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:H/A:H'}

Sat, 12 Sep 2026 00:15:00 +0000

Type Values Removed Values Added
Weaknesses CWE-125
References
Metrics threat_severity

None

 cvssV3_1

{'score': 4.7, 'vector': 'CVSS:3.1/AV:L/AC:H/PR:L/UI:N/S:U/C:N/I:N/A:H'}

threat_severity

Important

Fri, 11 Sep 2026 23:45:00 +0000

Type Values Removed Values Added
Description In the Linux kernel, the following vulnerability has been resolved: forcedeth: fix off-by-one when saving/restoring non-PCI config space nv_suspend() and nv_resume() walk the non-PCI configuration space with for (i = 0; i <= np->register_size/sizeof(u32); i++) which runs one iteration too many. saved_config_space is declared as u32 saved_config_space[NV_PCI_REGSZ_MAX/4]; and NV_PCI_REGSZ_VER3 is equal to NV_PCI_REGSZ_MAX (0x604), so on a VER3 device register_size/sizeof(u32) is exactly the array length and the last iteration addresses one element past the end. The element it lands on is np->name_rx[0..3]: saved_config_space[] is followed immediately by char name_rx[IFNAMSIZ + 3], and char needs no padding. Nothing observable is corrupted by that, because nv_request_irq() rewrites name_rx with sprintf() before it is ever passed to request_irq(). The bug is the out-of-bounds access itself, which UBSAN reports and which CONFIG_UBSAN_TRAP=y turns into a trap that aborts the running kernel code, plus an MMIO read and, on resume, an MMIO writel() to base + 0x604, one dword past the range the driver mapped: np->base = ioremap(addr, np->register_size); VER1 and VER2 devices stay inside the array, but they too get the stray read and the stray write one dword past their own window. Caught by UBSAN on an Apple Macmini3,1 (MCP79) during a deep S3 cycle. The splat below is trimmed: the build path in the file name, the CPU and taint lines, the Workqueue line, the "?" hint frames, and the frames below device_suspend are all cut. The kernel was tainted, with an out-of-tree nouveau and CPU_OUT_OF_SPEC; forcedeth itself was the stock module. UBSAN: array-index-out-of-bounds in drivers/net/ethernet/nvidia/forcedeth.c:6225:25 index 385 is out of range for type 'u32 [385]' Call Trace: dump_stack_lvl+0x5d/0x80 ubsan_epilogue+0x5/0x2b __ubsan_handle_out_of_bounds.cold+0x54/0x59 __this_module+0xe398c/0xe9010 [forcedeth] pci_pm_suspend+0x80/0x170 dpm_run_callback+0x51/0x160 device_suspend+0x1a2/0x4a0 ... Both loops are hit. UBSAN reports each source location only once per module load (__ubsan_handle_out_of_bounds() calls suppress_report(), which does test_and_set_bit(REPORTED_BIT, ...) on the struct source_location), so the two splats land in the first S3 cycle after the module is loaded and later cycles are silent even though the access still runs off the end every time. In that first cycle line 6225 is reported from pci_pm_suspend and line 6240 from pci_pm_resume. The same off-by-one was fixed in nv_get_regs() by commit ba9aa134287f ("forcedeth: fix buffer overflow") in 2012; these two loops were missed. The suspend and resume side was reported on LKML in September 2013 by Marc Weber, with the same analysis and the same one-character fix, but the patch was attached rather than sent inline and the thread ended there. Use < instead of <=, which saves and restores exactly register_size bytes.
Title forcedeth: fix off-by-one when saving/restoring non-PCI config space
First Time appeared Linux
Linux linux Kernel
CPEs cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*
Vendors & Products Linux
Linux linux Kernel
References

Subscriptions

Linux Linux Kernel
cve-icon MITRE

Status: PUBLISHED

Assigner: Linux

Published:

Updated: 2026-09-13T06:31:27.911Z

Reserved: 2026-09-11T19:38:34.731Z

Link: CVE-2026-89596

cve-icon Vulnrichment

No data.

cve-icon NVD

Status : Received

Published: 2026-09-11T20:19:44.310

Modified: 2026-09-13T07:17:24.997

Link: CVE-2026-89596

cve-icon Redhat

Severity : Important

Publid Date: 2026-09-11T19:44:58Z

Links: CVE-2026-89596 - Bugzilla

cve-icon OpenCVE Enrichment

Updated: 2026-09-13T04:45:18Z

Weaknesses